20-60A adjustable ~200vdc current mode buck design
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Posted by John Barrett on February 19, 2007, 4:06 am
Please log in for more thread options I'm looking to build a power supply for a krypton arc lamp, and need a design that can deliver an adjustable 20-60 amps into a LOW resistance load (around 5 ohms). I'm a programmer for a living and this is my first power electronics project (previous electronics projects have mostly been microcontroller based stuff) I've done quite a bit of reading, but am running into a brick wall scaling up some of the various designs that I've found online. I'm working with LTC's SWCad3 to test concepts, but I'm having problems with input currents spiking up way too high since my target output is so close to my current source (AC 220v 60A single phase rectified to 320vdc), and the 120hz line is just too slow to keep the input capacitor bank charged under heavy load without some serious high current spikes to recharge. Any suggestions to smooth out the current draw from the line would be MUCH appreciated !! | ||||||||||||||||
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Posted by Rene Tschaggelar on February 19, 2007, 5:53 am
Please log in for more thread options John Barrett wrote: John, such a power supply is rather tricky. The power level is rather high, and the nonlinear negative dynamic impedance load doen't make it simpler. You'll have to use a switching approach. Not recommended. Rene -- Ing.Buero R.Tschaggelar - http://www.ibrtses.com & commercial newsgroups - http://www.talkto.net | ||||||||||||||||
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Posted by on February 19, 2007, 6:59 am
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> and the 120hz line is
> just too slow to keep the input capacitor bank charged under heavy load > without some serious high current spikes to recharge. The old-fashioned way: ----------- ~ + ------ L ------------ + | bridge === --- | ----------- ~ - --------------------- - 'L' smoothes the charge peaks, needs an air gap, and will basically be a very heavy big piece of iron with copper. The output of this circuit is somewhat lower then 220V DC, so more current. See: http://tpub.com/neets/book7/27f.htm | ||||||||||||||||
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Posted by bernado on February 19, 2007, 7:36 am
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IPM - International Perforation Management high-tech engineering China-Germany-Thailand fax : 0049 - (0) 1212-5-375-17-531 http://www.microperforation.com http://www.microperforation.com.cn http://www.deguodaguan.com/ipm/ http://www.dk3qv.de Email : info@dk3qv.de - werner-grosse@web.de We are using AC/DC converters and special DC constanter with 300 V/DC 30 up to 60 Amps for nano or micro perforation machines since more then 20 years. There are several companies very well equiped - have a look to http://www.kfactor.it or http://www.irem.it Such AC/DC STABLIZED power supplies are to purchase by around 4000 - 6000 bucks by one year guarantee so that it makes not sense to invest several 10,000 bucks in developments for NEW primary AC switching and secondary DC regulated units. Let me know if you need more or specific details - I'm glad to help and support you. | ||||||||||||||||
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Posted by John Barrett on February 19, 2007, 8:19 am
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> IPM - International Perforation Management
> high-tech engineering China-Germany-Thailand > fax : 0049 - (0) 1212-5-375-17-531 > http://www.microperforation.com > http://www.microperforation.com.cn > http://www.deguodaguan.com/ipm/ > http://www.dk3qv.de > Email : info@dk3qv.de - werner-grosse@web.de > > We are using AC/DC converters and special DC constanter with 300 V/DC > 30 up to 60 Amps for nano or micro perforation machines since more > then 20 years. > > There are several companies very well equiped - have a look to > http://www.kfactor.it or http://www.irem.it > > Such AC/DC STABLIZED power supplies are to purchase by around 4000 - > 6000 bucks by one year guarantee so that it makes not sense to invest > several 10,000 bucks in developments for NEW primary AC switching and > secondary DC regulated units. > > Let me know if you need more or specific details - I'm glad to help > and support you. > The only detail that could possibly help me at those kinds of prices is "do you give free samples ??" :) :) I makes very little sense to invest that kind of money when I've got less than $500 into this laser so far, and I dont think its going to cost me more than about $1000 more to bring it online. I'm not being funded by a corporation with deep pockets :) In any case, for that kind of money, I could afford to pump this rod with 808nm laser diode bars and skip the massive current requirements that the krypton arcs are forcing me to deal with. ($6,000 times the 3 supplies I need pays for a LOT of laser diode bars !!) And I seriously doubt its going to cost me 10K or better to to design my own -- even if I count my time invested -- I'm pretty close to something workable now with less than a week invested, and between the folks here and what I'm finding online, working out the rest of the issues shouldnt take all that long. And besides -- I get to learn something new in the process !! <BigGrin>
[Flame On] So save the commercial hype for someone that doesnt want to be bothered with the nitty gritty details !! [Flame Off] | ||||||||||||||||
> design that can deliver an adjustable 20-60 amps into a LOW resistance load
> (around 5 ohms). I'm a programmer for a living and this is my first power
> electronics project (previous electronics projects have mostly been
> microcontroller based stuff)
>
> I've done quite a bit of reading, but am running into a brick wall scaling
> up some of the various designs that I've found online. I'm working with
> LTC's SWCad3 to test concepts, but I'm having problems with input currents
> spiking up way too high since my target output is so close to my current
> source (AC 220v 60A single phase rectified to 320vdc), and the 120hz line is
> just too slow to keep the input capacitor bank charged under heavy load
> without some serious high current spikes to recharge.
>
> Any suggestions to smooth out the current draw from the line would be MUCH
> appreciated !!